I used the magical search feature and no dice, so I turn you you magical beasts for some insight. If nothing else, there will be somewhere for people to search/reference in the future!

The X has been running great, well good enough, lately with no issues. I left work the other morning, and apparently the X didn't want to wake up that early. As soon as I started it up, the check engine light came on and it was running like crap. Had a bad hesitation all the way home. It feels like it is misfiring, but only under load. It doesn't do it if I brake torque it or Rev it up. Only while driving.

The codes I am getting are in the P035x family (typed that way for future searches). P0353 and P0358 are the codes I am getting (along with 4x4 codes for the vacuum solenoind...but that's the solution to other problems not relevant to this!). Being codes for the primary circuit, I popped the hood and checked out the connectors. Both connectors are fine, and tightly connected. I did notice however that cylinders 3 and 8 have other than OEM coil packs on them. These are the only 2 cylinders with those coil packs (they are white and the other 8 cylinders have black coils).

I don't want to just throw parts at it, and I'm not getting a hard miss fire code, just the 2 above. I might try to swap the coils with other cylinders tonight and see if the codes move to those cylinders. It has run like this a few times, but never set a code, and turning it off and back on has "fixed"this in the past.

And just for complete disclosure, while looking for where I saved a password, I found notes from August last year where I pulled codes, and these two codes were present then, with a cylinder 7 hard miss fire code. I replaced the c7 coil with motorcraft cleared the codes, and P0353 and P0358 went away and I haven't seen them since. The plugs are brand new and only have about 1000 miles on them (changed them in September when repairing the misfire and I don't drive it much).

Does anyone have some words of wisdom?

 

What kind of plugs? What engine? (Add truck info to your Sig for future searches) :-)

 

Sorry I thought it was in my signature, but it doesn't show up for me on the mobile.

It is a 6.8 V10
Motorcraft plugs

 

I think you are on the right path suspecting the aftermarket coils. Even the expensive Accell cops can cause issues on modular motors. Hopefully the swaptronics will let you know if it is a coil issue.

 

I got lucky and my buddy left his scan tool in the truck when he left, so tonight when I get off I'm going to clear the codes, swap the coils, and see what happens

 

Swap tonics was inconclusive. I swapped 3 and 8 with 2 and 7, cleared the codes, and drove it. It didn't hesitate and the cel didn't come back on. There were no pending codes either. I guess now we wait until the light comes back on and see if it's the same code as before or a 2 and 7 now.

 

Give the boots and springs a good scrutinizing if it comes back as well. They can arc out like a spark plug wire. Gotta love the CND. Op chk gd.

 

What should I be looking for

 

Make sure theres no cracks in the boots, even tiny ones. Make sure the spring inside the boots are in their proper locations- they should contact the coil at one end, and the plug at the other. Being spring-type material, sometimes they lose their stretch. This was the cause of one of my misfires on mine- the spring wasn't contacting the plug, forcing an intermittent "connection" whenever the spark felt like making the jump.

The boots/springs are pretty cheap- if the problem didn't follow the coils, and you suspect a boot (or boots), it wouldn't hurt the wallet much to change 'em.

 

I moved the whole thing, boot coil and spring together. I'm going to drive it around town short distances for a few days and see if I can get the light to come back on.

 

If it turns out you need them, 671-0001 is the denso part number for all ten boots and springs. The pics on some retailers show plug wires, but you will get boots and springs.

 

So i have put almost 100 miles on the truck since i swapped the coils to other cylinders. No codes as of yet. I am going to attribute it to water in the plug wells, because it had been pouring all night before i got the codes. Nothing else has changed, except it is dry now.

My buddy ended up giving me his OBDII dongle, so i downloaded the FORscan program, and this thing is pretty awesome! It reads every module in the truck, and can even do module tests and controls. Control over the ABS pump, the GEM, everything. I can even turn the ac compressor on and off with the program!

I found codes for 4x4 solenoid (which i figured was broken because the auto hubs don't work with new vacuum lines), and one for a PATS antenna not connected.